(1) Field of the Invention
This invention relates to a light emitting diode (LED) packaging, and more particularly to a high brightness LED packaging with a heat spreader.
(2) Description of Related Art
Light emitting diodes (LEDs) are small solid-state illuminators, which transform electric energy to cold illumination with high efficiency. The LED is a semiconductor pn junction diode specified with a pn junction surface. When a voltage is applied to the pn junction, electrons and holes are segregated toward the pn junction surface and then combined to release photons.
FIG. 1 shows a cross-section view of a traditional LED packaging 100. The LED packaging 100 includes a LED die 120, an anode metal lead 160, and a cathode metal lead 140. The LED die 120 is located on the top of the anode metal lead 160 and electrically connected to the cathode metal lead 140 by using a conductive wire 180. In addition, a transparent plastic body 190, which may be formed of resin, encapsulates the LED die 120 for protection.
Basically, the illumination of the LED die 120 is positively proportional to the current passing through the pn junction surface within the LED die 120. The density of the current has a limitation to prevent the pn junction surface from being breakthrough. Thus, it is understood that for applying a greater current to the LED die 120, the pn junction surface area must be increased. However, as the traditional LED packaging 100 shown in FIG. 1 is concerned, the greater current is attending with a huge amount of heat segregated in the LED packaging and reduces the illumination efficiency of the LED die 120.
Accordingly, how to release the heat generated in the LED packaging by the great current passing through the pn junction has become an important issue of high illumination LED industry.